The present invention relates to a writing pen for photosensitive material which can write a drawing, symbol, character or the like on heat developing type photosensitive material.
In order to write a drawing, symbol, character or the like in an overlapped manner on the photosensitive material in which record has already been made after exposure and heat development, the following methods have been employed in general so far. That is to say, the record is made by re-exposing and re-heat developing in accordance with the drawing, symbol, character or the like to be recorded, or the drawing, symbol, character or the like is recorded on the photosensitive material by ink, regardless of the optical change of the photosensitive material. The former method, however, takes time and various processes and thus is very inconvenient. In the latter method, if the photosensitive material on which the record has been made by ink is handled for further processes before the ink dries up, the photosensitive material is made dirty by the ink and accordingly a wait for drying the ink is required, so that this latter method also takes time.
Heat developing type photosensitive material has a characteristic that a portion thereof which has not been developed does not show an optical change no matter how the portion was exposed and that the optical change occurs only when the photosensitive material is heated. As a result, if the exposed photosensitive material is heat developed partially in the form of drawing, symbol or character, the optical change occurs at that portion where the photosensitive material is heat developed, so that the drawing, symbol, character or the like can be further recorded on the photosensitive material. Among the photosensitive materials, activating type photosensitive material has a characteristic that the photosensitive material is not excited unless the photosensitive material is exposed in a condition where the photosensitive material is activated by heating the material. As a result, if the exposed photosensitive material is heat developed partially in the form of drawing, symbol, character or the like, the optical change occurs at the portion where the photosensitive material is heat developed, so that the drawing, symbol, character or the like can be further recorded in the photosensitive material.